Axle assembly

ABSTRACT

An axle assembly having an input pinion with a pinion gear, which is received in an axle housing and rotatable about a first axis, and a pinion shaft. The pinion gear is meshed with a ring gear that is coupled to a differential assembly. A head bearing, which is disposed on a first axial end of the input pinion, supports the input pinion for rotation relative to the housing about the first axis. A tail bearing supports the input pinion for rotation relative to the housing about the first axis. The pinion gear is disposed axially between the tail bearing and the head bearing. A bearing groove is formed into the pinion shaft and the bearing elements are received into the bearing groove such that an inner bearing race of the tail bearing is unitarily and integrally formed with the pinion shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/205,535 filed Mar. 12, 2014, which claims the benefit of U.S.Provisional Patent Application No. 61/787,547 filed Mar. 15, 2013. Thedisclosure of each of the above-identified patent applications isincorporated by reference as if fully set forth in detail herein.

FIELD

The present disclosure relates to an axle assembly.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Modern automotive vehicles, particularly light trucks, typically employbeam axles that are constructed in the style of a Banjo-type axle or aSalisbury-type axle. As is known in the art, a Banjo-type axle employs ahousing that is fabricated of two identical beam halves, which arewelded to one another on the front and rear edges where the beam halvesabut one another. A housing for a conventional Banjo-type axle isdisclosed in U.S. Pat. No. 2,674,783. As is also known in the art, aSalisbury-style axle employs a housing that includes a center carrierand a pair of axle tubes that are pressed into or otherwise permanentlyaffixed to the center carrier. A housing for a Salisbury-type axle isdisclosed in U.S. Pat. No. 7,878,059.

While such axle housings are satisfactory for their intended purposes,there remains a need in the art for an improved axle assembly.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In one form, the present teachings provide an axle assembly thatincludes a housing, an input pinion, a ring gear, a differentialassembly, a head bearing and a tail bearing. The input pinion has apinion gear and a pinion shaft. The input pinion is received in thehousing and is rotatable about a first axis. The ring gear is meshedwith the pinion gear and is rotatable about a second axis that istransverse to the first axis. The differential assembly has adifferential case and a pair of output members. The differential case isdriven by the ring gear. The head bearing supports the input pinion forrotation relative to the housing about the first axis. The head bearingis disposed on a first axial end of the input pinion. The tail bearingsupports the input pinion for rotation relative to the housing about thefirst axis. The tail bearing has a plurality of bearing elements, aninner race and an outer race. The pinion gear is disposed axiallybetween the tail bearing and the head bearing. A bearing groove isformed into the pinion shaft. The bearing elements are received into thebearing groove such that the inner bearing race is unitarily andintegrally formed with the pinion shaft.

In some forms of this axle assembly, (a) the bearing elements comprisebearing balls; (b) the tail bearing is an angular contact bearing; (c)the tail bearing is a four-point contact ball bearing; (d) the outerrace comprises a first outer race member and a second outer race memberthat are axially separated from one another; (e) the axle assemblyfurther includes a bearing adjuster that is threadably coupled to thehousing, the bearing adjuster being configured to move the first outerbearing race member axially toward the second outer bearing race memberto pre-load the tail bearing; (f) the axle assembly further includes apinion shaft seal that is mounted to the housing, the pinion shaft sealhaving at least one lip seal that is sealingly engaged to the shaftportion; (g) the at least one lip seal is received axially through thebearing adjuster; (h) the axle assembly further includes a yoke flangenon-rotatably coupled to the input pinion; (i) the input pinion definesan internal cavity that is formed through a second, opposite axial end,wherein the input pinion has a first coupling portion having a pluralityof internal spline teeth, that border the internal cavity, and whereinthe yoke flange includes a second coupling portion that is received intothe internal cavity, the second coupling portion having a plurality ofexternal spline teeth that matingly engage the internal spline teeth;(j) a snap ring is received onto the second coupling portion and engagesa shoulder formed on the first coupling portion to thereby inhibit axialmovement of the yoke flange relative to the input pinion in a directionthat withdraws the second coupling portion from the first couplingportion; (k) the axle assembly further includes a pinion shaft seal thatis mounted to the housing, the pinion shaft seal having at least one lipseal that is sealingly engaged to the shaft portion; (l) the yoke flangeincludes a bearing shield that extends radially outwardly from thesecond coupling portion to cover an axial end of the pinion shaft seal;(m) the yoke flange is unitarily and integrally formed with the inputpinion; (n) the yoke flange is formed of aluminum; and/or (o) the headbearing includes a plurality of bearing elements, wherein the piniongear comprises a cylindrical extension, and wherein the bearing elementsof the head bearing are in direct contact with a surface of thecylindrical extension.

In another form, the present teachings provide an axle assembly thatincludes a housing, an input pinion, a ring gear, a differentialassembly, and a ring gear bearing. The input pinion has a pinion gearand is received in the housing for rotation about a first axis. The ringgear is meshed with the pinion gear and is rotatable about a second axisthat is transverse to the first axis. The differential assembly has adifferential case and a pair of output members. The differential case isdriven by the ring gear. The ring gear bearing supports the ring gearfor rotation relative to the housing about the second axis. The ringgear bearing has a plurality of bearing elements, an inner race and anouter race. A bearing groove is formed into the ring gear. The bearingelements are received into the bearing groove such that the outerbearing race is unitarily and integrally formed with the ring gear.

In some forms of this axle assembly, (a) the bearing elements comprisebearing balls; (b) the ring gear bearing can be an angular contactbearing; (c) the ring gear bearing can be a four-point contact bearing;(d) the inner race can include a first inner race member and a secondinner race member that are axially separated from one another along thesecond axis; (e) the axle assembly can further include a bearingadjuster that can be threadably coupled to the housing and configured tomove the first inner bearing race member axially toward the second innerbearing race member to pre-load the ring gear bearing; (f) the outerrace can include a first outer race member and a second outer racemember that can be axially separated from one another along the secondaxis; (g) the housing can have a first housing member and a secondhousing member that contact one another in a housing plane that isperpendicular to the second axis; (h) the second housing member can beconfigured to apply a force that is transmitted through the first outerbearing race to preload the ring gear bearing; (i) the differentialassembly can include a differential gearset having a plurality ofdifferential pinions and a pair of side gears that are meshed with thedifferential pinions; (j) a ball bearing having a plurality of bearingballs can support the input pinion for rotation relative to the housing,the differential pinions can be disposed about differential pinion axesfor rotation relative to the differential case, the differential pinionaxes can be disposed in a first bearing plane, and the first bearingplane can be located along the second axis between a second bearingplane extending through centers of the bearing balls of the ring gearand a plane extending perpendicular to the second axis and through oneof the bearing balls of the ball bearing that supports the input pinionthat is closest to the first bearing plane; (k) each of the differentialpinions can have a pinion shaft that is received into a mount structuredefined by the differential case; (l) the ring gear can support thedifferential case for rotation relative to the housing; (m) thedifferential case can be directly engaged to the ring gear such thatrotary power is transmitted directly from the ring gear to thedifferential case; (n) the differential assembly can include adifferential gearset having a plurality of differential pinions and apair of side gears that are meshed with the differential pinions; (o)the differential pinions can be directly engaged to the ring gear suchthat rotary power is transmitted directly from the ring gear to thedifferential pinions; (p) at least a portion of the differential pinionsare mounted on a cross-pin for rotation and the cross-pin is directlyengaged to the ring gear such that rotary power is transmitted directlyfrom the ring gear to the cross-pin; (q) at least a portion of thedifferential assembly can be supported for rotation relative to thehousing on a pair of differential bearings, and a first one of thedifferential bearings is intersected by a plane that extends through acenter of the bearing elements in the ring gear bearing; (r) the housingcan have a first housing member and a second housing member that canadjoin one another about a plane that is perpendicular to the secondaxis; and/or (s) the differential case can be formed of sheet metal.

In still another form, the present teachings provide an axle assemblythat includes a housing, an input pinion, a ring gear and a differentialassembly. The input pinion has a pinion gear. The input pinion isreceived in the housing and is rotatable about a first axis. The ringgear is meshed with the pinion gear and is rotatable about a second axisthat is transverse to the first axis. The differential assembly has adifferential gearset and a differential case. The differential gearsethas a plurality of bevel pinions and a pair of side gears that aremeshingly engaged to the bevel pinions. The differential case has a casemember and a plurality of pinion mounts. A first axial end of the casemember is fixed to the ring gear for rotation therewith. The pinionmounts are assembled to the case member. The pinion mounts arenon-rotatably coupled to the case member and are configured to supportthe bevel pinions for rotation relative to the case member aboutrespective bevel pinion axes.

In some forms of this axle assembly, (a) the pinion mounts can beslidable relative to the case member in an axial direction along thesecond axis; (b) the housing has a first housing member and a secondhousing member that adjoin one another about a plane that isperpendicular to the second axis; (c) the axle assembly includes a pairof axle shafts and each of the side gears is axially and non-rotatablycoupled to a corresponding one of the axle shafts; (d) each of the axleshafts has a threaded inboard portion and wherein a threaded fastenerengages the threaded inboard portion to axially fix an associated one ofthe side gears to the threaded inboard portion; (e) the threadedfasteners comprise nuts; (f) the axle assembly further includes a pairof inboard axle shaft bearings, each of the inboard axle shaft bearingssupporting an associated one of the axle shafts for rotation relative tothe housing, and wherein each of the threaded fasteners produces apreload force that is transmitted through the associated one of the sidegears and into an associated one of the inboard axle shaft bearings; (g)the axle assembly further includes a pair of outboard axle shaftbearings, each of the outboard axle shaft bearings supporting acorresponding one of the axle shafts; (h) each axle shaft includes ashaft member and a wheel flange that is welded to an axial end of theshaft member; (i) each axle shaft comprises a wheel flange having ashoulder formed thereon, and wherein the outboard axle shaft bearingsare abutted against the shoulders; (j) the axle assembly furtherincludes a pair of outboard axle shaft seals, each of the outboard axleshaft seals being sealingly engaged to the housing and a correspondingone of the wheel flanges; (k) axial positioning of the pinion mountsalong the second axis is based in part on positions of the side gearsalong the second axis relative to the housing and an amount by which theside gears are axially separated from one another along the second axis;(l) the case member defines a set of teeth that are disposed parallel tothe second axis and wherein the pinion mounts define a plurality ofmating teeth that matingly engage the set of teeth defined by the casemember; (m) the pinion mounts are formed of plastic; (n) the pinionmounts are formed of powdered metal; (o) the pinion mounts are formed ofcast metal; and/or (p) the case member is welded to the ring gear.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a schematic illustration of an exemplary vehicle having a(rear) axle assembly constructed in accordance with the teachings of thepresent disclosure;

FIG. 2 is a longitudinal section view of the axle assembly of FIG. 1;

FIG. 3 is an enlarged portion of FIG. 2, illustrating an input pinion, aring gear, a differential assembly and a portion of an axle housing inmore detail;

FIG. 4 is an exploded perspective view of a portion of the axle assemblyof FIG. 1, illustrating the input pinion, a head bearing and a tailbearing in more detail;

FIG. 4A is a longitudinal sectional view of the input pinion shown inFIG. 4;

FIG. 4B is an enlarged view of a portion of FIG. 4B;

FIG. 5 is a section view taken along the line 5-5 of FIG. 3;

FIG. 6 is an enlarged portion of FIG. 2, illustrating a wheel end of theaxle assembly in more detail;

FIG. 7 is a view similar to that of FIG. 2 but illustrating another axleassembly constructed in accordance with the teachings of the presentdisclosure;

FIG. 8 is an enlarged portion of FIG. 7, illustrating an input pinion, aring gear, a differential assembly and a portion of an axle housing inmore detail;

FIG. 9 is an enlarged portion of FIG. 7, illustrating a wheel end of theaxle assembly in more detail;

FIGS. 10 and 11 are views similar to that of FIG. 3 but illustrating twoother axle assemblies constructed in accordance with the teachings ofthe present disclosure; and

FIGS. 12 and 13 are left and right side perspective views of a portionof a differential assembly constructed in accordance with the teachingsof the present disclosure;

FIG. 14 is a perspective view of a portion of an axle housingconstructed in accordance with the teachings of the present disclosure;

FIGS. 15 through 17 are views similar to that of FIG. 6 but illustratingthree other axle assemblies constructed in accordance with the teachingsof the present disclosure;

FIG. 18 is a section view of a portion of another axle assemblyconstructed in accordance with the teachings of the present disclosure;

FIG. 19 is a perspective view of a portion of the axle assembly of FIG.18, illustrating a lock plate and a first locking dog in more detail;

FIG. 20 is a perspective view of a portion of the axle assembly of FIG.18, illustrating a pinion mount structure and a second locking dog inmore detail;

FIG. 21 is a perspective view of a portion of the axle assembly of FIG.18, illustrating a portion of a locking mechanism in more detail;

FIG. 22 is a perspective view of a portion of the axle assembly of FIG.18, illustrating the interlocking of adjacent pinion mount structures;

FIG. 23 is a perspective view of a portion of another axle assemblyconstructed in accordance with the teachings of the present disclosure;

FIG. 24 is a stepped section view of the axle assembly of FIG. 23,having a first portion taken through a hypoid axis of an input pinionparallel to a rotational axis of a differential assembly, and a secondportion taken through the rotational axis of the differential assemblyparallel to the hypoid axis;

FIG. 24A is a longitudinal section view of a portion of another axleassembly constructed in accordance with the teachings of the presentdisclosure;

FIG. 25 is a longitudinal section view of a portion of yet another axleassembly constructed in accordance with the teachings of the presentdisclosure, the view depicting the mounting of the ring gear on innerand outer ring gear bearings; and

FIG. 26 is a longitudinal section view of a portion of still anotheraxle assembly constructed in accordance with the teachings of thepresent disclosure, the view depicting the mounting of the ring gear ona pair of inner ring gear bearings.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

With reference to FIG. 1 of the drawings, an exemplary vehicle having anaxle assembly (e.g., a rear axle assembly) constructed in accordancewith the teachings of the present disclosure is generally indicated byreference numeral 10. The vehicle 10 can have a power train 12 and adrive line or drive train 14. The power train 12 can be conventionallyconstructed and can comprise a power source 16 and a transmission 18.The power source 16 can be configured to provide propulsive power andcan comprise an internal combustion engine and/or an electric motor, forexample. The transmission 18 can receive propulsive power from the powersource 16 and can output power to the drive train 14. The transmission18 can have a plurality of automatically or manually-selected gearratios. The drive train 14 in the particular example provided is of atwo-wheel, rear-wheel drive configuration, but those of skill in the artwill appreciate that the teachings of the present disclosure areapplicable to other drive train configurations, including four-wheeldrive configurations, all-wheel drive configurations, and front-wheeldrive configurations. The drive train 14 can include a prop shaft 20 anda rear axle assembly 22. The propshaft 20 can couple the transmission 18to the rear axle assembly 22 such that rotary power output of thetransmission 18 is received by the rear axle assembly 22. The rear axleassembly 22 can distribute the rotary power to the rear vehicle wheels26.

With reference to FIGS. 2 and 3, the rear axle assembly 22 can include ahousing 30, an input pinion 32, a ring gear 34, a differential assembly36, and a pair of axle shafts 38. The input pinion 32 can be rotatableabout a first axis 40, while the ring gear 34 and the differentialassembly 36 can be rotatable about a second axis 42 that can betransverse (e.g., perpendicular) to the first axis 40.

With reference to FIG. 3, the housing 30 can comprise first and secondhousing structures 46 and 48, respectively, that can be fixedly butremovably coupled to one another. The first and second housingstructures 46 and 48 can cooperate to define a differential cavity 50into which the differential assembly 36 can be received.

The first housing structure 46 can comprise a first carrier member 54and a first axle tube 56. The first carrier member 54 can be formed ofan appropriate material, such as cast iron or aluminum, and can define apinion bore 58, a first tube collar 60, and a first joint flange 62. Thepinion bore 58 can extend along the first axis 40 and can be configuredto receive the input pinion 32. The first tube collar 60 can be atubular structure that can be configured to receive the first axle tube56. The first axle tube 56 can be a hollow structure that can bepress-fit into the first tube collar 60. One or more slug welds (notshown) can be employed to inhibit axial and/or radial movement of thefirst axle tube 56 relative to the first carrier member 54.

The second housing structure 48 can comprise a second carrier member 64and a second axle tube 66. The second carrier member 64 can be formed ofan appropriate material, such as sheet or plate steel, and can define asecond tube collar 70 and a second joint flange 72. The second tubecollar 70 can be a tubular structure that can be configured to receivethe second axle tube 66. A plurality of threaded fasteners 76 (only oneshown) can be employed to fixedly but removably couple the secondcarrier member 64 to the first carrier member 54 such that the first andsecond joint flanges 62 and 72 abut or adjoin one another in a planethat is perpendicular to the second axis 42. In the particular exampleprovided, the threaded fasteners 76 are thread-forming screws that arereceived through holes (not specifically shown) in the second jointflange 72 and driven into holes (not specifically shown) in the firstjoint flange 62 to both form threads in the first carrier member 54 (ontheir initial installation to the first carrier member 54) and togenerate a clamp load that secures the first and second carrier members54 and 64 to one another. A seal member, such as a gasket 80, can bedisposed between and sealingly engaged to the first and second carriermembers 54 and 64. The second axle tube 66 can be a hollow structurethat can be received in the second tube collar 70 and fixedly coupled tothe second carrier member 64. In the particular example provided, thesecond axle tube 66 is welded to the second tube collar 70.

With reference to FIGS. 3 and 4, the input pinion 32 can include apinion gear 90 and a pinion shaft 92 that can be fixed to and rotatewith the pinion gear 90. In the particular example provided, the piniongear 90 and the pinion shaft are integrally and unitarily formed from asingle piece of steel. The input pinion 32 can be received in the pinionbore 58 in the housing 30 and can be supported for rotation relative tothe housing 30 about the first axis 40 by a head bearing 96, which canbe disposed on a first axial end of the input pinion 32, and a tailbearing 98 that can be disposed on a second, opposite axial end of theinput pinion 32. The pinion gear 90 can be disposed along the first axis40 axially between the head bearing 96 and the tail bearing 98.

The head bearing 96 can comprise a plurality of bearing elements 100, aninner bearing race 102 and an outer bearing race 104. The bearingelements 100 can be any type of element that can roll relative to theouter and inner bearing races 102 and 104. In the particular exampleprovided, the bearing elements 100 are cylindrically-shaped rollers. Theinner bearing race 102 can be formed on a cylindrical extension 110 thatextends from the pinion gear 90 on a side opposite the pinion shaft 92.The bearing elements 100 of the head bearing 96 can be in direct contactwith the cylindrical surface of the cylindrical extension 110. The outerbearing race 104 can be received in a pocket 114 formed in the firstcarrier member 54 and fixedly coupled the first carrier member 54 (e.g.,via a press-fit).

The tail bearing 98 can have a plurality of bearing elements 120, aninner bearing race 122 and an outer bearing race 124. The bearingelements 120 can be any type of element that can roll relative to theinner and outer bearing races 122 and 124. In the particular exampleprovided, the bearing elements 120 comprise bearing balls. The innerbearing race 122 can comprise a bearing groove 130 that can be formedinto a desired portion of the input pinion 32, such as the pinion shaft92. The bearing elements 120 can be received into the bearing groove 130such that the inner bearing race 122 is unitarily and integrally formedwith the pinion shaft 92. The outer bearing race 124 can be received ina bearing bore 136 formed in the first carrier member 54. The tailbearing 98 can be an angular contact bearing, but in the particularexample provided, the tail bearing 98 is a four-point contact ballbearing in which the bearing balls make contact at two points with thesurface of the bearing groove 130 and with first and second outer racemembers 140 and 142, respectively, which cooperate to form the outerrace 124. The first outer race member 140 can be axially separated fromthe second outer race member 142 along the first axis 40. A bearingadjuster 150 can be threadably engaged to the first carrier member 54and can be configured to move the first outer bearing race member 140toward the second outer bearing race member 142 to preload the tailbearing 98. The bearing adjuster 150 can be formed of sheet steel andcan have a threaded outside diameter 152 and a hollow tool engagingportion 154 through which the pinion shaft 92 can extend. The toolengaging portion 154 has an octagonal shape in the example provided,which permits the bearing adjuster 150 to be installed using a socketwrench. The bearing adjuster 150 can be deformable to allow a portion ofit to be staked into a recess formed in the first carrier member 54 toinhibit rotation of the bearing adjuster 150 after the preload on thetail bearing 98 has been set.

With specific reference to FIG. 4, the input pinion 32 can define aninternal cavity 160, which can extend through the pinion shaft 92 on aside opposite the pinion gear 90, and a first coupling portion 162 thatcan be fixedly and non-rotatably coupled to a second coupling portion164 on a yoke flange 166. In the example provided, the first couplingportion 162 comprises a plurality of internal spline teeth that borderthe internal cavity 160. The internal spline teeth of the first couplingportion 162 can be configured to matingly engage external spline teethformed on the second coupling portion 164. An axial retaining means,such as a snap ring, a screw or one or more stakes formed in a stakingoperation, can be employed to retain the yoke flange 166 to the inputpinion 32. For example, a snap ring 168 can be received in a groove 170in the second coupling portion 164 and abutted against a feature, suchas a shoulder 174, on the first coupling portion 162 to thereby axiallyfix the second coupling portion 164 to the first coupling portion 162.It will be appreciated, however, that the axial retaining means used inaddition to the internal and (mating) external spline teeth is optional.It will also be appreciated that other means for retaining the yokeflange 166 to the input pinion 32 could be employed, such as a pluralityof barbs or serrations on one or both of the yoke flange 166 and theinput pinion 32.

If desired, the second coupling portion 164 on the yoke flange 166 couldbe formed by pressing a pin portion 900 of the yoke flange 166 into theinternal cavity 160. For example, the input pinion 32 could besufficiently hardened (steel) and pin portion 900 of the yoke flange 166could be formed a relatively softer material, such as an unhardenedsteel or aluminum, which could deform as the pin portion 900 is pressedinto the internal cavity 160. In some instances, the input pinion 32could function as a broach-like tool that machines the pin portion 900as it is inserted into the internal cavity 160. With additionalreference to FIGS. 4A and 4B, the internal cavity 160 and the internalspline teeth 902 of the first coupling portion 162 can cooperate to forma structure that is configured to both machine mating external splineteeth onto the yoke flange 166 and to contain the chips or swarf that isformed when the mating external spline teeth are formed. Each of theinternal spline teeth 902 can be formed with a frustoconically-shapedface 904 that tapers away from a rear end 906 of the input pinion 32with increasing distance from the first axis 40. The amount of taper canbe about 5 degrees to about 20 degrees (as measured from thefrustoconically-shaped face 904 to a line perpendicular to the firstaxis 40), and preferably about 15 degrees. The radially inward edge 908of each frustoconically-shaped face 904 can be left sharp, while theradially outward edge of each frustoconically-shaped face 904 can blendinto an undercut radius 910 that defines a forward end of an annularchip containment compartment 912. A rearward end of the chip containmentcompartment 912 can be defined by a radially inwardly extending wallmember 914. The radially inwardly extending wall member 914 can beformed in any manner that is desired, such as tapering inwardly towardthe first axis 40 with increasing distance from the internal splineteeth 902. The chip containment compartment 912 is a space that isdisposed about the pin portion 900 of the yoke flange 166 when the pinportion 900 is pressed into the internal cavity 160 to form the secondcoupling portion 164. It will be appreciated that the radially inwardedges 908 of the frustoconically-shaped faces 904 form broach-likecutting elements and that the frustoconically-shaped faces 904 directthe chips (created when the second coupling portion 164 is formed) in aradially outward direction. The rounded geometry of the undercut radius910 can urge the chips to curl back gently to lessen the likelihood thatthe chips jam against the input pinion 32 and possibly impart additionalloading when the yoke flange 166 is pressed onto the input pinion 32.The chips generated during the formation of the second coupling portion164 can be contained in the chip containment compartment 912 between theundercut radius 910 and the radially inwardly extending wall member 914.Preferably, the radially inwardly extending wall member 914 issufficiently close in diameter to the pin portion 900 so that theradially inwardly extending wall member 914 pilots or aligns the pinportion 900 concentrically to the internal spline teeth 902 (and bothfore and aft of the internal spline teeth 902) prior to and during theformation of the mating spline teeth on the second coupling portion 164.

For example, the pin portion 900 of the second coupling portion 164 cancomprise first and second portions that are formed on opposite sides ofthe external spline teeth 164 and the first and second portions of thepin portion 900 can slidingly engage first and second surfaces of theinternal cavity 160 over distances that are longer along the first axis40 than a length of the internal spline teeth 162. Also preferably, theradially inwardly extending wall member 914 is sufficiently close indiameter to the pin portion 900 so that the radially inwardly extendingwall member 914 forms a barrier that inhibits the egress of chips from arearward end of the chip containment compartment 912.

Coupling of the yoke flange 166 to the input pinion 32 can be performed,for example, after the input pinion 32 has been installed to the firstcarrier member 54 and is supported by the tail bearing 98. So that theload associated with the pressing of the yoke flange 166 to the inputpinion 32 is not directed to the bearing elements 120 of the tailbearing 98, the input pinion 32 could be supported by an anvil (notshown) that could be received through a hole (not shown) formed in thefirst carrier member 54 (FIG. 3). The anvil could be removed after theyoke flange 166 has been pressed to the input pinion 32 and the hole inthe first carrier member 54 (FIG. 3) could be plugged. The hole couldhave other uses, such as for inspection of a portion of the axleassembly 22 (FIG. 2) and/or for filling the first carrier member 54(FIG. 3) with a lubricant, and as such, the plug could be removablycoupled to the first carrier member 54 (FIG. 3). Alternatively, the pinportion 900 of the yoke flange 166 can be hollow and a tool, which canbe threaded into a threaded hole 32-1 in the input pinion 32, could beemployed to force the yoke flange 166 and the input pinion 32 together(e.g., hydraulically). Moreover, a bolt (not shown) could be insertedthrough a hole (not shown) in the yoke flange 166 and threadably engagedto the threaded hole 32-1 in the input pinion 32 to axially and/orrotationally fix the yoke flange 166 to the input pinion 32.

Returning to FIG. 3, a pinion shaft seal 180 can be received between thehousing 30 and the pinion shaft 92 of the input pinion 32. In theparticular example provided, the pinion shaft seal 180 comprises anannular connection member 182, which is fixedly and sealingly engaged toa tubular portion 184 of the first carrier member 54, and a seal member186 that is fixed to an internal end of the connection member 182. Theseal lip 186 can comprise one or more sealing lips that can be sealinglyengaged to the pinion shaft 92. One or more of the sealing lips on theseal member 186 can be received axially through the bearing adjuster 150and sealingly engaged to the pinion shaft 92. Alternatively, the pinionshaft seal 180 could sealingly engage against a portion of the yokeflange 166.

If desired, a bearing shield 190 can be employed to cover an axial endof the pinion shaft seal 180. In the particular example provided, thebearing shield 190 is unitarily and integrally formed with the yokeflange 166 and includes a radial member 192, which extends radiallyoutwardly from the second coupling portion 164, and a tubular member 194that can be coupled to a distal end of the radial member 192 and extendaxially toward the pinion gear 90.

The ring gear 34 can be meshed with the pinion gear 90 and is rotatableabout the second axis 42. A ring gear bearing 200 can support the ringgear 34 for rotation relative to the housing 30 about the second axis42. The ring gear bearing 200 can comprise a plurality of bearingelements 202, an outer bearing race 204, and an inner bearing race 206.The bearing elements 202 can be any type of element that can rollrelative to the inner and outer bearing races 204 and 206. In theparticular example provided, the bearing elements 202 comprise bearingballs. The outer bearing race 204 can comprise a bearing groove 210 thatcan be formed into a desired portion of the ring gear 34, such as the inthe toe or inside diametrical surface of the ring gear 34. The bearingelements 202 can be received into the bearing groove 210 such that theouter bearing race 204 is unitarily and integrally formed with the ringgear 34. The inner bearing race 206 can be received on a hub 212 formedon the first carrier member 54. The ring gear bearing 200 can be anangular contact bearing, but in the particular example provided, thering gear bearing 200 is a four-point contact ball bearing in which thebearing balls make contact at two points with the surface of the bearinggroove 210 and with first and second inner race members 220 and 222,respectively, which cooperate to form the inner bearing race 206. Thefirst inner race member 220 can be axially separated from the secondinner race member 222 along the second axis 42.

A bearing adjuster 226 can be threadably engaged to the hub 212 and canbe configured to move the first inner bearing race member 220 toward thesecond inner bearing race member 222 to preload the ring gear bearing200. The bearing adjuster 226 can be formed of sheet steel and can havea threaded inside diameter 228, which can be threadably engaged to thehub 212, and a hollow tool engaging portion 230. The tool engagingportion 230 has an octagonal shape in the example provided, whichpermits the bearing adjuster 226 to be installed using a socket wrench.The bearing adjuster 226 can be deformable to allow a portion of it tobe staked into a recess formed in the first carrier member 54 to inhibitrotation of the bearing adjuster 226 after the preload on the ring gearbearing 200 has been set.

With reference to FIGS. 3 and 5, the differential assembly 36 caninclude a differential case 240, a pair of output members 242 and ameans 246 for permitting speed differentiation between the outputmembers 242. The differential case 240 can comprise a case member 250and a plurality of pinion mount structures 252. The case member 250 canbe formed of an appropriate material, such as sheet or plate steel, andcan define a ring gear flange 258 and a coupling portion 260. The ringgear flange 258 can be fixedly coupled to the ring gear 34 in anydesired manner, such as with a plurality of threaded fasteners (notshown). In the example provided, the ring gear flange 258 is welded tothe heel of the ring gear 34. The case member 250 can taper in agenerally frustoconical manner between the ring gear flange 258 and thecoupling portion 260. The coupling portion 260 can be a generallytubular structure that can be non-rotatably engaged to the pinion mountstructures 252 in any desired manner. In the example provided, thecoupling portion 260 includes a plurality of circumferentiallyspaced-apart spline teeth 264 that are formed parallel to and about thesecond axis 42.

The pinion mount structures 252 can be shaped in the form of annularsegments and can nest together to form an annular structure that can bereceived into the coupling portion 260. The pinion mount structures 252can be formed of a suitable material, such as a plastic (e.g.,glass-filled Nylon), a powdered metal or a cast metal (e.g., die castmetal). Each of the pinion mount structures 252 can include a pluralityof spline teeth 274 and a mount structure 276 that can be configured totransmit rotary power to the speed differentiation means 246. The splineteeth 274 can be formed on an exterior circumferential surface of thepinion mount structures 252 and can be configured to matingly engage thespline teeth 264 of the coupling portion 260.

The speed differentiation means 246 can comprise any means forpermitting speed differentiation between the output members 242. Forexample, the speed differentiation means 246 can include one or moreclutches, such as friction clutches (not shown), that can be operated topermit/control speed differentiation between the output members 242. Inthe particular example provided, the speed differentiation means 246comprises a differential gearset 280 having a plurality of differentialpinions 282 and a pair of side gears 284. Each of the differentialpinions 282 can include a pinion member 290 and a mating mount structure292 that is configured to engage the mount structure 276 of anassociated one of the pinion mount structures 252 to receive rotarypower therefrom. The pinion members 290 can be bevel pinion gears thatcan meshingly engage the side gears 284. Each of the output members 242can be fixedly and non-rotatably coupled to an associated one of theside gears 284. Each of the output members 242 can comprise aninternally splined structure that can be mounted on a corresponding oneof the axle shafts 38.

In the example provided, the mating mount structures 292 are hollowcylindrical shaft members and the mount structures 276 are holes intowhich the shaft members (mating mount structures 292) are received. Eachof the shaft members can be integrally and unitarily formed with anassociated one of the pinion members 290. It will be appreciated,however, that the shaft members could be discrete components that can befixedly coupled to one or more of the pinion members 290. The pinionmount structures 252 can be configured to support the pinion members 290for rotation relative to the case member about respective bevel pinionaxes 298.

The pinion mount structures 252 are slidable relative to the case member250 in an axial direction along the second axis 42. Axial positioning ofthe pinion mount structures 252 along the second axis 42 can be based inpart on positions of the side gears 284 along the second axis 42relative to the housing 30 and an amount by which the side gears 284 areaxially separated from one another along the second axis 42.Configuration in this manner permits the pinion mount structures 252 tofloat along the second axis 42 so that the differential gearset 280 candictate their position.

With reference to FIGS. 3 and 6, each of the axle shafts 38 can befixedly and non-rotatably coupled to an associated one of the outputmembers 242. Each of the axle shafts 38 can have a shaft member 304 anda wheel flange 306 that can be fixedly coupled to an axial outboard endof the shaft member 304. In the example provided, the shaft member 304is a hollow tube and is welded to the wheel flange 306 via a suitablewelding process, such as friction welding, but it will be appreciatedthat other fastening means, such as a splined connection that ismechanically fastened (e.g., threaded fasteners), could be employed inthe alternative. The shaft member 304 can have an inboard end (shown inFIG. 3), which can include an externally splined structure 310 and aplurality of threads 312, and an outboard end (shown in FIG. 6).

With reference to FIG. 3, the externally splined structure 310 can beconfigured to matingly engage the internally splined structure on anassociated one of the output members 242. A threaded fastener 320 can beengaged to the plurality of threads 312 to axially fix an associated oneof the output members 242 to a corresponding one of the shaft members304. The plurality of threads 312 can be external threads that can beformed inboard of the externally splined structure 310 and the threadedfastener 320 can comprise a nut. Any desired means can be employed toinhibit rotational movement of the nut relative to the axle shaft 38,including staking, adhesives, and/or a locking tab.

With reference to FIGS. 3 and 6, each axle shaft 38 can be supported forrotation relative to a corresponding one of the first and second axletubes 56 and 66 by an inboard axle shaft bearing 330 (FIG. 3) and anoutboard axle shaft bearing 332 (FIG. 6). The inboard axle shaft bearing330 can be any type of bearing, such as a tapered roller bearing, andcan include an outer bearing race 340 and an inner bearing race 350 thatcan be received on an associated one of the shaft members 304 andabutted against a corresponding one of the output members 242. The outerbearing races 340 can be received into a pocket 342 formed in an inboardaxial end of the hub 212 on the first carrier member 54 and a pocket 344formed in an inboard axial end of the second axle tube 66. In theexample provided, each of the threaded fasteners 320 is configured toproduce a preload force that is transmitted through one of the sidegears 284 and into one of the inboard axle shaft bearings 330.

The outboard axle shaft bearings 332 can be any type of bearing, such asa tapered roller bearing, and can include an outer bearing race 360,which can be received into a pocket 362 formed in an outboard axial endof the first axle tube 56 or the second axle tube 66, and an innerbearing race 364 that can be received on a shaft portion 366 of thewheel flange 306. The inner bearing race 364 can be abutted against ashoulder 370 formed on the wheel flange 306. A pair of outboard axleshaft seals 374 can be employed to form seals between the housing 30 andthe axle shafts 38. Each of the axle shaft seals 374 can be receivedinto an associated one of the first and second axle tubes 56 and 66 andcan have a lip seal 376 that can be sealingly engaged to a seal surface378 on the wheel flange 306.

It will be appreciated that as the present example employs taperedroller bearings for the inboard and outboard axle shaft bearings 330 and332, it is necessary to preload these bearings. While the axle assembly22 (FIG. 2) may be assembled in various different ways, we presentlyenvision that the axle shafts 38, the output members 242, the inboardand outboard axle shaft bearings 330 and 332, and the threaded fasteners320 can be assembled to the first and second housing structures 46 and48 prior to the assembly of the first and second housing structures 46and 48 to one another. The ring gear 34 and the ring gear bearing 200can be installed to the first housing structure 46. In either order, thedifferential pinions 282 can be assembled to the pinion mount structures252 and the pinion mount structures 252 can be installed to the couplingportion 260 of the differential case 240. The differential pinions 282can be meshed with the side gear 284 that is coupled to the axle shaft38 that is mounted in the first housing structure 46. The gasket 80 canbe mounted to the first carrier member 54. The second housing structure48 can be positioned relative to the first housing structure 46 to causethe side gear 284 that is coupled to the axle shaft 38 that is mountedin the second housing structure 48 to mesh with the differential pinions282. The second joint flange 72 on the second carrier member 64 can beadjoin the first joint flange 62 on the first carrier member 54.Depending on the configuration of the gasket 80, portions of the firstand second joint flanges 62 and 72 may actually abut (contact) oneanother as is the case in the illustrated example. Alternatively, thegasket 80 could be disposed between the first and second joint flanges62 and 72 so as to inhibit contact between the first and second jointflanges 62 and 72.

It will be appreciated that in the particular example provided, aportion of the differential assembly 36 (e.g., the side gears 284) issupported for rotation relative to the housing 30 via the inboard axleshaft bearing 330 and as such, the inboard axle shaft bearing 330functions in some degree as differential bearings. The inboard axleshaft bearing 330 in the first housing structure 46 can be disposedrelative to the ring gear bearing 200 such that a plane extendingthrough the centers of the bearing elements 202 of the ring gear bearing200 extends through the inboard axle shaft bearing 330 in the firsthousing structure 46. Stated another way, the inboard axle shaft bearing330 can be nested under or in-line with the bearing elements 202 of thering gear bearing 200.

With reference to FIGS. 7 and 8, a second axle assembly constructed inaccordance with the teachings of the present disclosure is generallyindicated by reference numeral 22 a. The second axle assembly 22 a canbe generally similar to the axle assembly 22 (FIG. 2), except for thedifferential assembly 36 a and the axle shafts 38 a.

With reference to FIG. 8, the differential assembly 36 a can include adifferential case 240 a, a pair of output members 242 a and a means 246a for permitting speed differentiation between the output members 242 a.The differential case 240 a can comprise a first case member 400, asecond case member 402 and a third case member 404, each of which beingformed of an appropriate material, such as sheet steel. The first casemember 400 can define a ring gear flange 258 a and a coupling portion260 a. The ring gear flange 258 a can be fixedly coupled to the ringgear 34 in any desired manner, such as with a plurality of threadedfasteners (not shown). In the example provided, the ring gear flange 258a is welded to the ring gear 34. The first case member 250 can taper ina generally frustoconical manner between the ring gear flange 258 a andthe coupling portion 260 a. The coupling portion 260 a can be fixedlyand non-rotatably coupled to the second case member 402. In the exampleprovided, the coupling portion 260 a is an annular flange member thatextends radially inwardly from a distal end of the frustoconical portionof the first case member 400 and is fixedly coupled (e.g., welded) to aradial flange member 410 on the second case member 402. The second andthird case members 402 and 404 are identical stampings and as such, onlythe second case member 402 will be discussed in detail. In addition tothe radial flange member 410, the second case member 402 can have agenerally spherical body portion 420, which can be disposed within theradial flange member 410, and a plurality of half-mounts 422. The secondand third case members 402 and 404 can be fixedly coupled at theirradial flange members 410 (e.g., via welding or threaded fasteners) suchthat the generally spherical body portions 420 cooperate to define acavity 430 into which the speed differentiation means 246 a can bereceived. The second and third case members 402 and 404 are coupled toone another such that the half-mounts 422 cooperate to define tubularmount structures 276 a.

The speed differentiation means 246 a can comprise any means forpermitting speed differentiation between the output members 242 a. Forexample, the speed differentiation means 246 a can include one or moreclutches, such as friction clutches (not shown), that can be operated topermit/control speed differentiation between the output members 242 a.In the particular example provided, the speed differentiation means 246a comprises a differential gearset 280 a having a plurality ofdifferential pinions 282 a and a pair of side gears 284 a. Each of thedifferential pinions 282 a can include a pinion member 290 a and a shaftmember 292 a that is received in and engaged to an associated one of thetubular mount structures 276 a to thereby receive rotary power from thedifferential case 240 a. The pinion members 290 a can be bevel piniongears that can meshingly engage the side gears 284 a. Each of the shaftmembers 292 a can be integrally and unitarily formed with an associatedone of the pinion members 290 a. It will be appreciated, however, thatthe shaft members 292 a could be discrete components that can be fixedlycoupled to one or more of the pinion members 290 a. The tubular mountstructures 276 a can be configured to support the pinion members 290 afor rotation relative to the case member about respective bevel pinionaxes 298. Each of the output members 242 a can be fixedly andnon-rotatably coupled to an associated one of the side gears 284 a. Eachof the output members 242 a can comprise an internally splined structurethat can be mounted on a corresponding one of the axle shafts 38 a.

With reference to FIGS. 8 and 9, each of the axle shafts 38 a can benon-rotatably coupled to an associated one of the output members 242 a.Each of the axle shafts 38 a can have a shaft member 304 a and a wheelflange 306 a that can be fixedly coupled to an axial outboard end of theshaft member 304 a. In the example provided, the shaft member 304 a is ahollow tube and is welded to the wheel flange 306 a via a suitablewelding process, such as friction welding. The shaft member 304 a canhave an inboard end (shown in FIG. 8), which can include an externallysplined structure 310 a, and an outboard end (shown in FIG. 9). Theexternally splined structure 310 a can be configured to matingly engagethe internally splined structure on an associated one of the outputmembers 242 a.

With reference to FIG. 9, each axle shaft 38 a can be supported forrotation relative to a corresponding one of the first and second axletubes 56 a and 66 a by an outboard axle shaft bearing 332 a. Theoutboard axle shaft bearings 332 a can be any type of bearing, such as atapered roller bearing, and can include an outer bearing race 360 a,which can be received into a pocket 362 a formed in an outboard axialend of the first axle tube 56 a or the second axle tube 66 a, and aninner bearing race 364 a that can be received on a shaft portion 366 aof the wheel flange 306 a. An outboard side of the inner bearing race364 a can be abutted against a shoulder 370 a formed on the wheel flange306 a and a wedding ring 450, which can be axially fixed to the shaftportion 366 a of the wheel flange 306 a, can be abutted an inboard sideof the inner bearing race 364 a. A pair of outboard axle shaft seals 374a can be employed to form seals between the housing 30 a and the axleshafts 38 a. Each of the axle shaft seals 374 a can be received into anassociated one of the first and second axle tubes 56 a and 66 a and canhave a lip seal 376 a that can be sealingly engaged to a seal surface378 a on the wheel flange 306 a.

With renewed reference to FIGS. 8 and 9, it will be appreciated that asthe present example employs tapered roller bearings for the outboardaxle shaft bearings 332 a, it is necessary to preload these bearings.While the axle assembly 22 a (FIG. 7) may be assembled in variousdifferent ways, we presently envision that the outboard axle shaftbearings 332 a are preloaded after the axle assembly 22 a (FIG. 7) hasbeen assembled. The axle assembly 22 a (FIG. 7) can include a preloadmechanism 460 that can be configured to apply a compressive force to theinboard axial ends of the axle shafts 38 a. The preload mechanism 460can comprise any suitable device, such as a jack screw, a suitably sizedspacer, or a cylinder. In the particular example provided, the preloadmechanism 460 comprises a cylinder 462 and a pair of thrust bearings464. The cylinder 462 is configured to be filled with an incompressiblefluid, such as a grease, that causes the cylinder 462 to elongate andapply a compressive force to the axle shafts 38 a. The grease can beinput to the cylinder 462 through a one-way valve, such as a Zerkfitting (not specifically shown). Each of the thrust bearings 464 can beabutted against a side of the cylinder 462 and an axial end of one ofthe axle shafts 38 a.

In FIG. 10, a portion of a third axle assembly 22 b constructed inaccordance with the teachings of the present disclosure is illustrated.The third axle assembly 22 b can be generally similar to the axleassembly 22 a (FIG. 7), except for the housing 30 b, the input pinion 32b, the ring gear 34 b, the ring gear bearing 200 b and the differentialcase 240 b. The housing 30 b is generally similar to the housing 30(FIG. 3), except that the housing 30 b additionally includes a thirdhousing structure 500 that is fixedly but removably coupled to the firstcarrier member 54 b. The third housing structure 500 comprises anintegral bearing seat 150 b that can be configured to move the firstouter bearing race member 140 toward the second outer bearing racemember 142 when the third housing structure 500 is installed to thefirst carrier member 54 to preload the tail bearing 98. A gasket 506 canbe received between the first carrier member 54 b and the third housingstructure 500.

The input pinion 32 b can be generally identical to the input pinion 32(FIG. 3), except that the yoke flange 166 b can be unitarily andintegrally formed with the pinion gear 90 and the pinion shaft 92 b froma single piece of steel. The internal cavity 160 b can extend throughthe yoke flange 166 b. The pinion shaft seal 180 b can be sealinglyengaged to the third housing structure 500 and sealingly engaged to thepinion shaft 92 b of the input pinion 32 b. The bearing shield 190 b canbe a discrete component that can be assembled to the input pinion 32 b.

The ring gear bearing 200 b can comprise a plurality of bearing elements202, an outer bearing race 204 b, and an inner bearing race 206 b. Theinner bearing race 206 b can comprise a bearing groove 210 b that can beformed into a desired portion of the ring gear 34 b, such as the in theheel or outside diametrical surface of the ring gear 34 b. The bearingelements 202 can be received into the bearing groove 210 b such that theinner bearing race 206 b is unitarily and integrally formed with thering gear 34 b. The outer bearing race 204 b can be received on a hub212 b formed on the first carrier member 54 b. The ring gear bearing 200b can be an angular contact bearing, but in the particular exampleprovided, the ring gear bearing 200 b is a four-point contact ballbearing in which the bearing balls make contact at two points with thesurface of the bearing groove 210 b and with first and second outer racemembers 220 b and 222 b, respectively, which cooperate to form the outerbearing race 204 b. The first outer race member 220 b can be axiallyseparated from the second outer race member 220 b along the second axis42. The second joint flange 72 b on the second carrier member 64 b canbe configured to move the first outer bearing race member 220 b towardthe second outer bearing race member 222 b to preload the ring gearbearing 200 b. If required, one or more shims (not shown) can bedisposed between the second joint flange 72 b and the first outerbearing race member 220 b.

The differential case 240 b is similar to the differential case 240 a(FIG. 8) except that the second and third case members 402 b and 404 bare directly coupled to the ring gear 34 b so that the first case member400 (FIG. 8) is not required. In the particular example provided, theradial flange members 410 b of the second and third case members 402 band 404 b define a plurality of external teeth 510 that are engaged tointernal teeth 512 formed on the inside diametrical surface of the ringgear 34 b. Accordingly, it will be appreciated that rotary power can betransmitted directly from the ring gear 34 b to the differential case240 b and that the ring gear 34 b supports the differential case 240 bfor rotation relative to the housing 30 b.

In the particular example illustrated, the differential pinions 282 aare disposed about differential pinion axes 298 for rotation relative tothe differential case 240 b, the differential pinion axes 298 aredisposed in a first bearing plane 520, and the first bearing plane 520is located along the second axis 42 between a second bearing plane 522,which extends through centers of the bearing balls of the ring gear 34b, and a plane 524 that extends perpendicular to the second axis 42 andthrough one of the bearing balls of the tail bearing 98 that is locatedclosest to the first bearing plane 522.

In FIG. 11, a portion of a fourth axle assembly 22 c constructed inaccordance with the teachings of the present disclosure is illustrated.The fourth axle assembly 22 c can be generally similar to the axleassembly 22 b (FIG. 10), except for the differential assembly 36 c. Thedifferential assembly 36 c includes a differential gearset 280 c havinga cross-pin 550 that is received in the mount structure 276 c in thedifferential case 240 c and into slots 552 formed in the ring gear 34 c.The differential case 240 c is formed of two case halves that are notfixedly coupled to one another in the example provided. Tabs on the casehalves can be received into the slots 552 in the ring gear 34 c so thatthe case halves are rotatably coupled to the ring gear 34 c. Thedifferential pinions 282 c are rotatably mounted on the cross-pin 550.Rotary power can be transmitted directly from the ring gear 34 c to thecross-pin 550 (and to the differential case 240 c). A thrust bearing 556can be received between the differential case 240 c and the housing 30c. Proximal ends of the axle shafts 38 c can abut the cross-pin 550. Asnap ring 560 can be received in a ring groove 562 in each axle shaft 38c and the snap ring 560 can abut an inboard surface of a correspondingone of the side gears 284 c. Alternatively, the cross-pin 550 can bedeleted and differential pinions similar to the differential pinions 282a (FIG. 8) can be employed. In this alternative example, the shaftmember 292 a (FIG. 8) can be extended somewhat so as to be received intoa corresponding one of the slots 552 in the ring gear 34 c so that thedifferential pinions 282 a (FIG. 8) are directly engaged to the ringgear 34 c such that rotary power is transmitted directly from the ringgear 34 c to the differential pinions 282 a (FIG. 8).

While not shown, the axle shafts 38 c can “float” at the wheel ends. Inthis regard, the outboard ends of the axle shafts 38 c can be mounted oncylindrical roller bearings. It will be appreciated, however, that othermounting configurations for the axle shafts 38 c could be employed inthe alternative.

In FIGS. 12 and 13, a portion of an alternately constructed differentialcase 240 d is illustrated. The differential case 240 d includes a firstcase member 250 d with a ring gear flange 258 d that includes aplurality of projections or embossments 570 that are configured to bereceived into corresponding holes or slots (not shown) in a ring gear(not shown). Threaded fasteners (not shown) can be received throughholes 572 in the ring gear flange 258 d and threadably engaged tothreaded holes (not shown) in the ring gear.

In FIG. 14, an alternately constructed bearing adjuster 226 d isillustrated as being threadably mounted on a threaded portion of the hub212 on the first carrier member 54. The bearing adjuster 226 d comprisesa plurality of locking features, such as teeth 590, on its outercircumferential surface. A locking bracket 592 can have a mating lockingfeature, such as mating teeth 594, that can matingly engage the lockingfeatures on the bearing adjuster 226. The locking bracket 592 can befixedly coupled to the first carrier member 54. In the particularexample provided, a bolt (not shown) is employed to removably secure thelocking bracket 592 to the first carrier member 54.

In the examples of FIGS. 15 through 17, different outboard axle bearingand wheel flange configurations are depicted. In FIG. 15, the outboardaxle bearing 332 e has an inner bearing race 364 e that is integrallyformed with the shaft portion 366 e of the wheel flange 306 e. The outerbearing race 360 e can comprise first and second race members 600 and602, which permit bearing elements, such as rollers 604, to be receivedin an undercut bearing surface 606 on the shaft portion 366 e. Aretainer 610 can be employed to retain the axle shaft seal 374 e and theouter bearing race 360 e in the first axle tube 56 e or the second axletube 66 e.

The example of FIG. 16 is generally similar to that of FIG. 15, exceptthat the outboard axle bearing 332 f is a ball bearing, the bearingsurface 606 f is a groove for receiving the bearing balls 604 f and theouter bearing race 360 f is formed in a single piece.

The example of FIG. 17 is similar to that of FIG. 16 except that itemploys a four-point contact ball bearing for the outboard axle bearing332 g in which the inner bearing races 620, 622 comprise bearingsurfaces 606 g (i.e., grooves) that are formed directly into the shaftportion 366 g of the wheel flange 306 g. Additionally, the wheel flange306 g employs a plurality of external spline teeth 650 that matinglyengage internal spline teeth 652 on the shaft member 304 g tonon-rotatably but axially movably couple the wheel flange 306 g to theshaft member 304 g.

In FIG. 18, a portion of another axle assembly constructed in accordancewith the teachings of the present disclosure is generally indicated byreference numeral 22 h. The axle assembly 22 h can be generally similarto the axle assembly 22 (FIG. 2) except that the differential assembly36 h includes a locking mechanism 700 that is configured to inhibitspeed differentiation between the output members 242 h. The lockingmechanism 700 can comprise a lock plate 702, a return spring 704, afirst locking dog 706, a second locking dog 708, and a linear motor 710.

With additional reference to FIG. 19, the lock plate 702 can be formedof hardened stamped steel sheet or plate and can include a splinedinternal aperture 714 and an annular rim 716 that can be locatedconcentrically about and radially outwardly of the splined internalaperture 714. The splined internal aperture 714 can define a pluralityof spline teeth that can be non-rotatably but axially slidably engagedto mating splined teeth formed on one of the output members 242 h/sidegears 284 h. The return spring 704 can be any device that can bias thelock plate 702 in a direction away from the differential pinions 282 andthe pinion mount structures 252 h. In the particular example provided,the return spring 704 comprises a wave spring that is received over theone of the output members 242 h into a groove 720 formed on an axial endface of an associated one of the side gears 284 h. The first locking dog706 can be fixedly coupled to the annular rim 716 of the lock plate 702.In the example provided, the first locking dog 706 comprises projections724 that are formed when the lock plate 702 is stamped, but it will beappreciated that the first locking dog 706 could have teeth, pins or anyother type of locking device that can be formed as a discrete componentand assembled to the lock plate 702.

With reference to FIGS. 18 and 20, the second locking dog 708 can becoupled to the differential case 240 h and/or to the pinion mountstructures 252 h. In the particular example provided, the second lockingdog 708 is integrally formed with the pinion mount structures 252 h andcomprises a plurality of recesses 728 formed into a side of the pinionmount structures 252 h that are configured to matingly receive theprojections 724 (FIG. 19) of the first locking dog 706. In the exampleprovided, the pinion mount structures 252 h are formed of powdered metaland as such, the recesses 728 are configured with draft to permit thedies (not shown) that are employed to form the pinion mount structures252 h to be separated from one another to eject the pinion mountstructures 252 h after they are formed.

Returning to FIG. 18, the linear motor 710 can be any type of devicethat is configured to translate the lock plate 702 along the second axis42. In the particular example provided, the linear motor 710 is asolenoid and comprises a lock plate mount 730, an armature 732, a coil734, and a coil mount 736. The lock plate mount 730 can be configured tocouple the lock plate 702 to the armature 732 at least when the armature732 is moved in a predetermined axial direction. In the particularexample provided, the lock plate mount 730 is formed of a plasticmaterial that is overmolded onto (i.e., cohesively bonded to) thearmature 732. The lock plate mount 730 can define a radially inwardlyextending lip member 740 that can be received about the annular rim 716of the lock plate 702. The lip member 740 is not fixedly coupled to theannular rim 716 in the example provided, but is configured to contactthe annular rim 716 when the armature 732 (and therefore the lock platemount 730) is moved in an axial direction toward the coil 734. Thearmature 732 can be an annular structure that can be formed of aferromagnetic material. The armature 732 can be generally L-shaped incross-section with a sloped end 744 on its axially-extending leg 746.The coil 734 can be wound on a bobbin structure 748 that can be fixedlycoupled to the coil mount 736.

With reference to FIG. 21, the coil mount 736 can comprise a pluralityof cantilevered fingers 750. The cantilevered fingers 750 can have barbs(not specifically shown) at their distal ends that can be engaged in asnap-fit manner to a rim member 754 on the housing 30 h. The rim member754 can comprise a section or strip of generally L-shaped sheet steelthat can be welded to the second carrier member 64 h. Returning to FIG.18, the coil mount 736 can include a coupling portion 756 that isconfigured to be coupled to a wire harness (not shown). The couplingportion 756 can be received into a boss 758 formed in the second carriermember 64 h. A seal 760 can be mounted to the coupling portion 756 andcan be sealingly engaged to the coupling portion 756 and the boss 758 toinhibit the ingress of fluids into and the egress of fluid from thehousing 30 h. While the particular linear motor described herein andillustrated in the appended drawings includes an electromagnet, it willbe appreciated that other linear motors could be employed in thealternative, including pneumatic cylinders and hydraulic cylinders.

With reference to FIGS. 20 and 22, the pinion mount structures 252 h canbe formed such that their ends 770 and 772 interlock with one another.Each of the ends 770 can comprise a plurality of first tabs 780 and aplurality of first recesses 782, while each of the ends 772 can comprisea plurality of second tabs 790 and a plurality of second recesses 792.Each of the second recesses 792 can be configured to receive acorresponding one of the first tabs 780, while each of the firstrecesses 782 can be configured to receive a corresponding one of thesecond tabs 790. The tabs and recesses on each of the ends 770 and 772should be staggered such that the ends 770 and 772 interlock (andthereby support one another as is shown in FIG. 18) when adjacent pinionmount structures 252 h are assembled to one another.

In FIGS. 23 and 24, a portion of another axle assembly constructed inaccordance with the teachings of the present disclosure is generallyindicated by reference numeral 22 i. The axle assembly 22 i can begenerally similar to the axle assembly 22 h (FIG. 18) except that thedifferential case 240 i is integrally formed with a case member 250 iand the pinion mounts 252 i. In the particular example provided, thedifferential case 240 i is a hollow tubular structure that is formed ofa powdered metal material that is consolidated and heat-treated. Thecase member 250 i of the differential case 240 i can be fixedly coupledto the ring gear 34 by any desired method. In the particular exampleprovided, a plurality of first teeth 800 on the case member 250 i aremeshingly and matingly engaged with a plurality of second teeth 802formed on a hub portion 804 of the ring gear 34 and the case member 250i is additionally welded (e.g., laser welded) about its outer diameterto hub portion 804. While the differential case 240 i can extend throughthe hub portion 804, it need not extend completely through the entirering gear 34 (e.g., the case member 250 i need not extend to a positionradially inwardly of the ring gear teeth 806 that mesh with the piniongear teeth 808 of the input pinion 32).

The pinion mounts 252 i can be configured to support the pinion members290 of the differential pinions 282 for rotation relative to the casemember 250 i about respective bevel pinion axes 298. Alternatively, thepinion mounts 252 i could be configured to receive a conventionalcross-pin (not shown) onto which conventional bevel pinions (not shown)could be rotatably received. The conventional cross-pin can be fixed tothe differential case 240 i in any desired manner, such as thosedescribed in commonly assigned U.S. Pat. No. 7,976,422 entitled“Differential With Cross Pin Retention System And Method For Assembly”,the disclosure of which is incorporated by reference as if fully setforth in detail herein.

Construction in this manner can be advantageous, for example, to permitthe bearing elements 202 of the ring gear bearing 200 to bespaced-axially apart but disposed axially in-line along the second axis42 with the case member 250 i, so that the differential assembly 36 ican be constructed in a radially compact manner in which the headbearing 96 is also disposed axially in-line with the case member 250 ialong the second axis 42. In this arrangement, one of the axle shafts 38that is coupled to one of the side gears 284 for rotation therewithextends through the ring gear 34, and the case member 250 i is disposedradially outwardly of and about the inboard axle shaft bearing 330 thatsupports the one of the axle shafts 38 relative to the first carriermember 54. Also in this arrangement, the ring gear 34 is positionedaxially along the second axis 42: a) between the differential case 240 iand the input pinion 32; b) between the bevel pinions 282 and the inputpinion 32; and c) between the side gears 284 and the input pinion 32.

While the axle assembly 22 i has been described and illustrated as beingan axle assembly with an open differential assembly, those of skill inthe art will appreciate that the axle assembly 22 i could optionally beequipped with a locking mechanism 700 (FIG. 18) that is configured toinhibit speed differentiation between the side gears 284. In thisembodiment, the second locking dog 708 i comprises a plurality of teeth728 i that are integrally formed with the differential case 240 i andconfigured to matingly engage corresponding teeth or projections 724(FIG. 19) on the lock plate 702 (FIG. 18) of the first locking dog 706(FIG. 18). Like the above-described embodiment, the lock plate 702 (FIG.18) can be translated (e.g., via linear motor 710 (FIG. 18)) toselectively couple the differential case 240 i to the one of the outputmembers 242 h/side gears 284 h (FIG. 18).

The example of FIG. 24A is generally similar to the example of FIGS. 23and 24, except for the configuration of the differential assembly 36 i-1and the mounting of the inboard and outboard axle shaft bearings 330 iand 332. The differential assembly 36 i-1 can include a unitarily formeddifferential case 240 i-1 and a differential gearset 280 c that has thecross-pin 550, differential pinions 282 c rotatably mounted on thecross-pin 550, and a pair of side gears 284 i-1. The differential case240 i-1 can be splined to the ring gear 34 i-1 as described above and assuch, can float axially along the second axis 42 relative to the ringgear 34 i-1.

The inboard and outboard axle shaft bearings 330 i and 332 i can bereceived pockets formed in the hub 212 i of the first carrier member 54i and in the axle tube 66 i, respectively, and an axle shaft bearingpreload nut 320 i can be threadably engaged to the axle shafts 38 i-1 atrespective locations that are outboard of both the differential case 240i-1 and the side gears 284 i-1. Additionally, the differential case 240i-1 can pilot on a locating portion 38 i-2 of the outboard axle shaft 38i-1. In this example, the differential case 240 i-1 can float in anaxial direction along the second axis 42.

While the ring gear has been illustrated and described as including asingle bearing, such as an annular contact bearing (e.g., a four-pointcontact ball bearing), it will be appreciated that the ring gear couldbe supported by a plurality of bearings. In FIG. 25 for example, thering gear 34 j is supported by an inner ring gear bearing 200 j-1 and anouter ring gear bearing 200 j-2.

The inner ring gear bearing 200 j-1 can comprise a plurality of bearingelements 202 j-1, an outer bearing race 204 j-1, and an inner bearingrace 206 j-1. The bearing elements 202 j-1 can be any type of elementthat can roll relative to the inner and outer bearing races 204 j-1 and206 j-1. In the particular example provided, the bearing elements 202j-1 comprise bearing balls. The outer bearing race 204 j-1 can comprisea bearing groove 210 j-1 that can be formed into a desired portion ofthe ring gear 34 j, such as the in the toe or inside diametrical surfaceof the ring gear 34 j. The bearing elements 202 j-1 can be received intothe bearing groove 210 j-1 such that the outer bearing race 204 j-1 isunitarily and integrally formed with the ring gear 34 j. The innerbearing race 206 j-1 can be received on a hub 212 j formed on the firstcarrier member 54 j and abutted against a shoulder 1000. The inner ringgear bearing 200 j-1 can be an angular contact bearing.

The outer ring gear bearing 200 j-2 can comprise a plurality of bearingelements 202 j-2, an outer bearing race 204 j-2, and an inner bearingrace 206 j-2. The bearing elements 202 j-2 can be any type of elementthat can roll relative to the outer and inner bearing races 204 j-2 and206 j-2. In the particular example provided, the bearing elements 202j-2 comprise bearing balls. The inner bearing race 206 j-2 can comprisea bearing groove 210 j-2 that can be formed into a desired portion ofthe ring gear 34 j, such as the in the outside diametrical surface ofthe ring gear 34 j. The bearing elements 202 j-2 can be received intothe bearing groove 210 j-2 such that the inner bearing race 206 j-2 isunitarily and integrally formed with the ring gear 34 j. The outerbearing race 204 j-2 can be received in a counterbore 1002 formed in thesecond carrier member 64 j and abutted against a shoulder 1004 on thesecond carrier member 64 j. A threaded adjuster 1006 can be threadablyengaged to the second carrier member 64 j and can be employed togenerate a preload that is applied to the inner and outer ring gearbearings 200 j-1 and 200 j-2.

Alternatively, a plurality of ring gear bearings could be employed tosupport the ring gear, either from its inner side or its outer side. Inthe example of FIG. 26, first and second ring gear bearings 200 k-1 and200 k-2 are employed to support the ring gear 200 k from its inner side.

The first ring gear bearing 200 k-1 can comprise a plurality of bearingelements 202 k-1, an outer bearing race 204 k-1, and an inner bearingrace 206 k-1. The bearing elements 202 k-1 can be any type of elementthat can roll relative to the outer and inner bearing races 204 k-1 and206 k-1. In the particular example provided, the bearing elements 202k-1 comprise bearing balls. The outer bearing race 204 k-1 can comprisea bearing groove 210 k-1 that can be formed into a desired portion ofthe ring gear 34 k, such as the in the toe or inside diametrical surfaceof the ring gear 34 k. The bearing elements 202 k-1 can be received intothe bearing groove 210 k-1 such that the outer bearing race 204 k-1 isunitarily and integrally formed with the ring gear 34 k. The innerbearing race 206 k-1 can be received on a hub 212 k formed on the firstcarrier member 54 k and abutted against a shoulder 1000 k. The firstring gear bearing 200 k-1 can be an angular contact bearing. A spacer1010 can be disposed between the first and second ring gear bearings 200k-1 and 200 k-2.

The second ring gear bearing 200 k-2 can comprise a plurality of bearingelements 202 k-2, an outer bearing race 204 k-2, and an inner bearingrace 206 k-2. The bearing elements 202 k-2 can be any type of elementthat can roll relative to the outer and inner bearing races 204 k-2 and206 k-2. In the particular example provided, the bearing elements 202k-2 comprise bearing balls. The outer bearing race 204 k-2 can comprisea bearing groove 210 k-2 that can be formed into a desired portion ofthe ring gear 34 k, such as the in the toe or inside diametrical surfaceof the ring gear 34 k. The bearing elements 202 k-2 can be received intothe bearing groove 210 k-2 such that the outer bearing race 204 k-2 isunitarily and integrally formed with the ring gear 34 k. The innerbearing race 206 k-2 can be received on the hub 212 k that is formed onthe first carrier member 54 k. The second ring gear bearing 200 k-2 canbe an angular contact bearing. A threaded adjuster 1006 k can bethreadably engaged to the hub 212 k of the second carrier member 64 kand can be employed to generate a preload that is applied to the firstand second ring gear bearings 200 k-1 and 200 k-2.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. An axle assembly comprising: a housing; an inputpinion having a pinion gear and a pinion shaft, the input pinion beingreceived in the housing and being rotatable about a first axis; a ringgear meshed with the pinion gear and rotatable about a second axis thatis transverse to the first axis; a differential assembly having adifferential case and a pair of output members, the differential casebeing driven by the ring gear; and means, consisting solely of a headbearing and a tail bearing, for supporting the input pinion for rotationrelative to the housing about the first axis, the head bearing beingdisposed on a first axial end of the input pinion and comprising aplurality of cylindrical bearing rollers, the tail bearing having asingle row of bearing elements, an inner race and an outer race, thepinion gear being disposed axially between the tail bearing and the headbearing; wherein a bearing groove is formed into the pinion shaft andwherein the bearing elements are received into the bearing groove suchthat the inner bearing race is unitarily and integrally formed with thepinion shaft.
 2. The axle assembly of claim 1, wherein the head bearingcomprises a plurality of bearing elements, wherein the pinion gearcomprises a cylindrical extension, and wherein the bearing elements ofthe head bearing are in direct contact with a surface of the cylindricalextension.
 3. The axle assembly of claim 1, wherein the bearing elementscomprise bearing balls.
 4. The axle assembly of claim 3, wherein thetail bearing is an angular contact bearing.
 5. The axle assembly ofclaim 4, wherein the tail bearing is a four-point contact ball bearing.6. The axle assembly of claim 5, wherein the outer race comprises afirst outer race member and a second outer race member that are axiallyseparated from one another.
 7. The axle assembly of claim 6, furthercomprising a bearing adjuster that is threadably coupled to the housing,the bearing adjuster being configured to move the first outer bearingrace member axially toward the second outer bearing race member topre-load the tail bearing.
 8. The axle assembly of claim 7, furthercomprising a pinion shaft seal that is mounted to the housing, thepinion shaft seal having at least one lip seal that is sealingly engagedto the pinion shaft.
 9. The axle assembly of claim 8, wherein the atleast one lip seal is received axially through the bearing adjuster. 10.The axle assembly of claim 1, further comprising a yoke flangenon-rotatably coupled to the input pinion.
 11. The axle assembly ofclaim 10, wherein the yoke flange is unitarily and integrally formedwith the input pinion.
 12. The axle assembly of claim 10, wherein theyoke flange is formed of aluminum.
 13. The axle assembly of claim 10,wherein the input pinion defines an internal cavity that is formedthrough a second, opposite axial end, wherein the input pinion has afirst coupling portion having a plurality of internal spline teeth, thatborder the internal cavity, and wherein the yoke flange includes asecond coupling portion that is received into the internal cavity, thesecond coupling portion having a plurality of external spline teeth thatmatingly engage the internal spline teeth.
 14. The axle assembly ofclaim 13, wherein the second coupling portion comprising first andsecond pin portions that are formed on opposite sides of the externalspline teeth, wherein the first and second pin portions slidingly engagefirst and second surfaces of the internal cavity over distances that arelonger along the first axis than a length of the internal spline teeth.15. The axle assembly of claim 13, wherein the second coupling portioncomprising first and second pin portions that are formed on oppositesides of the external spline teeth, wherein the first and second pinportions slidingly engage first and second surfaces of the internalcavity to align the pin portion to the first axis.
 16. The axle assemblyof claim 13, further comprising a pinion shaft seal that is mounted tothe housing, the pinion shaft seal having at least one lip seal that issealingly engaged to the pinion shaft.
 17. The axle assembly of claim16, wherein the yoke flange comprises a bearing shield that extendsradially outwardly from the second coupling portion to cover an axialend of the pinion shaft seal.
 18. The axle assembly of claim 13, whereinthe internal spline teeth are formed with a frustoconically-shaped facesthat tapers away from a rear end of the input pinion with increasingdistance from the first axis.
 19. The axle assembly of claim 18, whereina radially outward edge of each of the frustoconically-shaped facesintersect a chip containment compartment.
 20. The axle assembly of claim19, wherein a forward end of the chip containment compartment is definedby an undercut radius.
 21. The axle assembly of claim 19, wherein aradially inward edge of each of the frustoconically-shaped faces issharp, the frustoconically-shaped faces being adapted to cut theexternal spline teeth when the second coupling portion is inserted intothe internal cavity and driven axially against the internal splineteeth.
 22. An axle assembly comprising: a housing; an input pinionhaving a pinion gear and a pinion shaft, the input pinion being receivedin the housing and being rotatable about a first axis; a yoke flangenon-rotatably coupled to the input pinion; a ring gear meshed with thepinion gear and rotatable about a second axis that is transverse to thefirst axis; a differential assembly having a differential case and apair of output members, the differential case being driven by the ringgear; a head bearing supporting the input pinion for rotation relativeto the housing about the first axis, the head bearing being disposed ona first axial end of the input pinion; and a tail bearing supporting theinput pinion for rotation relative to the housing about the first axis,the tail bearing having a plurality of bearing elements, an inner raceand an outer race, the pinion gear being disposed axially between thetail bearing and the head bearing; wherein a bearing groove is formedinto the pinion shaft and wherein the bearing elements are received intothe bearing groove such that the inner bearing race is unitarily andintegrally formed with the pinion shaft; wherein the input piniondefines an internal cavity that is formed through a second, oppositeaxial end, wherein the input pinion has a first coupling portion havinga plurality of internal spline teeth, that border the internal cavity,and wherein the yoke flange includes a second coupling portion that isreceived into the internal cavity, the second coupling portion having aplurality of external spline teeth that matingly engage the internalspline teeth; and wherein the second coupling portion comprising firstand second pin portions that are formed on opposite sides of theexternal spline teeth, wherein the first and second pin portionsslidingly engage first and second surfaces of the internal cavity overdistances that are longer along the first axis than a length of theinternal spline teeth.
 23. An axle assembly comprising: a housing; aninput pinion having a pinion gear and a pinion shaft, the input pinionbeing received in the housing and being rotatable about a first axis; ayoke flange non-rotatably coupled to the input pinion; a ring gearmeshed with the pinion gear and rotatable about a second axis that istransverse to the first axis; a differential assembly having adifferential case and a pair of output members, the differential casebeing driven by the ring gear; a head bearing supporting the inputpinion for rotation relative to the housing about the first axis, thehead bearing being disposed on a first axial end of the input pinion;and a tail bearing supporting the input pinion for rotation relative tothe housing about the first axis, the tail bearing having a plurality ofbearing elements, an inner race and an outer race, the pinion gear beingdisposed axially between the tail bearing and the head bearing; whereina bearing groove is formed into the pinion shaft and wherein the bearingelements are received into the bearing groove such that the innerbearing race is unitarily and integrally formed with the pinion shaft;wherein the input pinion defines an internal cavity that is formedthrough a second, opposite axial end, wherein the input pinion has afirst coupling portion having a plurality of internal spline teeth, thatborder the internal cavity, and wherein the yoke flange includes asecond coupling portion that is received into the internal cavity, thesecond coupling portion having a plurality of external spline teeth thatmatingly engage the internal spline teeth; and wherein the secondcoupling portion comprising first and second pin portions that areformed on opposite sides of the external spline teeth, wherein the firstand second pin portions slidingly engage first and second surfaces ofthe internal cavity to align the pin portion to the first axis.